Warp switches



United States Patent 3,017,477 WARP SWITCHES Michael J. De Leonardis, Valley Stream, N.Y. Filed Mar. 13, 1956, Ser. No. 571,263 2 Claims. (Cl. 200-122) This invention relates to warp switches.

This application is a continuation-in-part of co-pending application Serial No. 449,592, now abandoned.

The warp switch may be employed to control the operation of any of a wide variety of means or a combination of means. It may for example be employed in a circuit to open a switch to turn off a pump when water employed to lift gasoline in a tank reaches a predetermined maximum level, or to turn off the motor of an oil burner when water in a boiler falls below a safe level, and to condition the motor circuit for turning on the motor when the water level in the boiler is above a safe level and the boiler thermostat or aquastat calls for heat.

An object of the invention is to provide an improved warp switch for use between an electric control circuit and an electric controlled circuit.

A further object of the invention is to provide a warp switch adapted for use in a control circuit operative with low resistance and low current consumption and requiring simple and inexpensive elements which may be assembled in a small space.

Another object of the invention is to provide an improved warp switch which will prevent a controlled c-ircuit from being repeatedly turned on and off at short intervals due to surging of liquid within a container, as for example in a boiler when the liquid is boiling, by provding a time delay between the opening or closing of the control circuit and the energization or deenergization of the controlled circuit. The time delay serves to prevent momentary closing and opening of the control circuit from affecting the controlled circuit.

Other objects of the invention will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements, arrangements of parts, and in the several steps and relation and order of each of said steps to one or more of the others thereof, all as will be pointed out in the following description, and the scope of the application of which will be indicated in the following claims.

The invention will best be understood if the following description is read in connection with the drawing, in which The drawing is a diagrammatic view of the warp switch embodying the invention, shown connected in a circuit which comprises a source of power, a heating element in a device to be controlled.

In the drawing is shown a warp switch which comprises arms 132, 134, 216 and 214. Arms 132 and 134 are bi-m-etallic and equally effected by changes in ambient temperature. Member 132 is substantially U-shaped and extends around a heat source 130, illustrated as a lamp. One leg of member 132 is extended to overlie the member 134 and to contact member 134 at 136 when member 132 has become heated above a predetermined temperature by heat radiated from member 130. The other end of arm 132 is connected by lead 202 to circuit to be controlled such, for example, as a boiler or other controlled circuit where time delay may be necessary, and i connected to ground at 203.

Bi-metallic member 134 is supported by means 140a and is connected by lead 142X to a power supply P, which in turn is connected at 148 to ground. Arms 214 and 216 are also mounted by means 140a. Arm 214 is connected to lead 142 and arm 216 is connected by lead 218 to heat vsource .130 which is also connected to ground at 121.

Projecting downwardly from bi-me'tal member 134 is an abutment member 160. When member 134 is not in contact with member 132, and when it is contacted by member 132 but not depressed by member 132, switch arms 216 and 214 remain in contact. However, when the heat source has continued energize-d for a sufficient period of time to cause arm 134 to warp sufficiently to contact with, and press down on arm 216, thus opening the circuit to the heat source and allowing arms 132 and 134 to cool and unbend until arm 214 again moves back into contact with arm 216, or until the source of power P is deenergized.

Applicant has obtained very satisfactory results using a house lighting circuit as the power source and lamps or bulbs of 4 to 10 watts as the element for slowly heating and cooling and thereby actuating said movable member when it becomes heated or cooled above or below a predetermined temperature, following turning on or off of the lamp.

As shown herein the support a for arm 134 serves also to support arms 214 and 216 and insulate them from one another and from arm 134.

When arms 214 and 216 are in contact a circuit is completed through the filament but when arm 214 is depressed enough to break the contact between arms 214 and 216 arm 132 will start cooling and will unbend in a short period, say one to one and a quarter minutes.

After arms 132 and 134 have been in contact for a period which can be predetermined arm 134 will be bent sufficiently for its extension to contact arm 214 and move it out of contact with arm 216. This action having been obtained before arms 132 and 134 could become unduly heated and bent arm 132 will speedily cool and return to position to break its contact with arm 134.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.

What I claim is:

1. A warp switch to operate in a region of varying ambient temperature comprising a member capable of being heated when a first electric circuit of which it forms a part is closed, a first heat responsive bimetallic arm positioned in operative relation to said heatable member, a second heat responsive bimetallic arm to compensate for warping of said first heat responsive bimetallic arms due to variation in the ambient temperature, said second heat responsive bimetallic arm positioned to be substantially unaffected directly by heat from said heatable member but extending into position to be contacted by said first arm when the latter has been slightly bent in response to heating of said heatable member, said second arm coacting with said first arm when contacted by said first arm to complete a second electric circuit, and means for preventing excessive heating and bending of said first and second bimetallic arms and thereby controlling the period required for said arms to separate and break said second electric circuit when said heatable member i deactuated by said means.

2. The warp switch claimed in claim 1 in which the means for preventing excessive bending of said bimetallic arms comprises a pair of contact members forming part of said first electric circuit, said contact members being normally in contact, and means actuated by bending of said second arm beyond a predetermined amount to separate said contact members periodically thus opening said first circuit until said bimetallic arms have cooled sufficiently to cause the second of said arms to unbend to a position within its range of bending which does not open the contact between said contact members.

References Cited in the file of this patent 4 Mesh Aug. 10, 1948 Spierer May 1, 1951 Connolly July 29, 1952 Reitz Aug. 24, 1954 Nichols Sept. 28, 1954 McCorkle May 1, 1956 Bruerrnan July 24, 1956 FOREIGN PATENTS Great Britain Aug. 17, 1931 

